It sounds like you see her quite a bit. I would be pretty explicit: "that's a great tradition for you guys, but it's not my thing at ALL."
Of course, sometimes people are just so determined to get you what they THINK you'll like that it doesn't matter what you want. My father was this way with, of all things, a tent! He kept saying how nice it would be if I had a tent, how we could go camping together (me in a tent, his family ib an air conditioned motor home ...), how I could camp anytime I wanted. And NO amount of "that doesn't sound like fun at all" or "if I wanted a tent, I'd have one," or "please do not geme a tent. I'll never, ever camp with you" or "we're hotel people, not campsite people" dissuaded him. He wanted me to want a tent, darn it. (And probably already had bought it or been given it before the hinting started). I got it and exchanged it, unopened, for a few pairs of shoes.
If she does give you one despite the necessary, explicit warnings to the contrary, my advice is to never wear it and to possibly return it. You are under no obligation to use it or participate in someone's tradition you don't care for. They probably won't get you any charms after that.